Some / any
http://www.autoenglish.org/gr.some.i.htm
http://www.eflnet.com/grammar/anysome.php
Can:
http://saberingles.com.ar/curso/lesson13/07.html
http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-5542.php
http://www.edu365.cat/primaria/muds/angles/can/avalua/index.htm
http://www.1-language.com/englishcourse/unit18_grammar_exs2.htm
http://www.saberingles.com.ar/curso/lesson13/05.html
http://www.englishexercises.org/makeagame/viewgame.asp?id=1518
http://www.1-language.com/englishcourse/unit18_grammar_exs.htm(extension)
Must/Mustn’t (obligation and prohibition)
http://www.englishgrammarsecrets.com/musthaveto/exercise2.swf
http://www.englishgrammarsecrets.com/musthaveto/exercise5.swf
http://www.english-grammar-lessons.com/musthaveto/exercise8.swf